Preparation, characterization and supercapacitive performance of graphene nanosheets from microcrystalline graphite

In this study, graphene nanosheets (GS) were prepared from a kind of economic and resourceful graphite material, natural microcrystalline graphite, by thermal exfoliation method. The scanning electron microscopy and transmission electron microscopy images show that the obtained GS have porous structure and are well separated and composed of approximately 6–8 wrinkled individual monoatomic graphene layers. The results of nitrogen adsorption–desorption analysis show the GS possess high specific surface area. The results of electrochemistry measurements show that the prepared GS have good supercapacitive performance, the capacitance increase with the oxidation degree of microcrystalline graphite oxide. The highest capacitive performance can reach 175 F g−1 at 0.5 A g−1, and also the GS have good rate performance and cycle stability.